WEDNESDAY, Dec. 2, 2015 (HealthDay News) -- American women diagnosed with advanced, stage 4 breast cancer have a better chance of survival, and are surviving longer, compared to two decades ago, a new study finds.
Stage 4 breast cancer involves a tumor that has spread -- metastasized -- beyond the breast and surrounding lymph nodes to other organs in the body.
"Survival in stage 4 breast cancer has improved and is increasingly of prolonged duration, particularly for some women undergoing initial breast surgery," report researchers led by Mary Schroeder, an assistant professor of health services research at the University of Iowa in Iowa City.
Her team published their findings online Dec. 2 in the journal JAMA Surgery.
One expert was heartened by the results.
"It is not surprising that there has been an improvement in length of survival in patients with stage 4 breast cancer, as there have been many advances in chemotherapeutic and immunologic therapies," said Dr. Stephanie Bernik, chief of surgical oncology at Lenox Hill Hospital in New York City.
"We have also gotten better at targeting specific kinds of cancers with drugs that are directed to treating certain tumor types, and are moving away from a 'one-size-fits-all' treatment regimen," Bernik said.
In its study, Schroeder's group tracked outcomes for more than 21,000 patients who were diagnosed with stage 4 breast cancer between 1988 and 2011. The women did not receive radiation therapy as part of their first course of treatment.
The investigators found that the patients' median survival rose from 20 months between 1988 and 1991, to 26 months between 2007 and 2011.
At the same time, rates of breast surgery declined during the study period. However, women who did undergo surgery were more likely to survive, the researchers found. Among patients diagnosed before 2002, nearly 10 percent of those who had surgery survived at least 10 years, compared with about 3 percent of those who did not have surgery.
Along with surgery, other factors associated with longer survival included the patient's marital status, her year of diagnosis, tumor size and the tumor's hormone receptor status (sensitivity to hormones can affect how aggressive a tumor might be).
Further research is needed to learn more about the link between surgery and improved survival, the researchers said.
Experts said that the value of surgically removing a breast when the cancer has already spread beyond it is still being debated.
"Why remove a woman's breast in the face of overt metastatic disease? This is not a new idea, with some retrospective, non-randomized trials showing that survival is increased if one removes the primary breast cancer," said Dr. Charles Shapiro, director of translational breast cancer research at Mount Sinai Health System in New York City.
"Why biologically this would be so is unclear," he said, but some theorize that removing the originating cancer might help the immune system battle the disease, or stop the primary tumor from "seeding" new tumors elsewhere in the body.
Dr. Richard Bleicher is a breast surgeon and associate professor at Fox Chase Cancer Center in Philadelphia. He pointed out that the Iowa study was retrospective -- not the gold standard prospective, randomized trial needed to say for sure that surgery does boost survival for women with stage 4 breast cancers.
While the current study does suggest a benefit, "it remains unclear, however, from this data, whether this is true for all women or particular subsets, and the study poses as many questions as it answers," he said.
"This study reinforces the suggestion that surgery is beneficial in stage 4 disease, but ultimately for the definitive word on this issue, we will need prospective data to sort out the issues of selection bias in this type of retrospective study," Bleicher said.
The U.S. National Cancer Institute has more about breast cancer treatment.